Computing - Boolean Algebra

2020-09-08
3 min read

Boolean Algebra

Boolean algebra is like writing algebraic expressions acting on variables. Boolean notation is the set of symbols that define logical operators on variables.

$$ P = \text{NOT} (A \text{AND} B) P = \overline{A \cdot B} $$

$$ P = (A \text{AND} B) \text{OR} C P = (A \cdot B) + C $$

NOT

$$ P = \text{NOT} A P = \overline{A} $$

What does the notation $\overline{A}$ in boolean algebra??

NOT.

AND

$$ P = A \text{AND} B P = A \cdot B $$

What does the notation $A \cdot B$ mean in boolean algebrea??

AND.

OR

$$ P = A \text{OR} B P = A + B $$

What does the notation $A + B$ mean in boolean algebra??

OR.

XOR

$$ P = A \text{XOR} B P = A \oplus B $$

What does the notation $A \oplus B$ mean in boolean algebra??

XOR.

NOR and NAND

Instead of having a special notation, you write these as boolean expressions themselves.

$$ P = \text{NOT} (A \text{OR} B) P = \overline{(A + B)} $$

What is NOR in boolean notation??

$$ \overline{(A+B)} $$

What is NAND in boolean notation??

$$ \overline{(A \cdot B)} $$

What is the order of operations for boolean algebra??
  1. Highest: NOT
  2. Middle: AND
  3. Lowest: OR

De Morgan’s Laws

Who was Augustus De Morgan??

August De Morgan was a mathematician who invented laws to simplify boolean expressions.

What is De Morgan’s first law??

$$ \overline{A} \cdot \overline{B} = \overline{A+B} $$

What is $\overline{A} \cdot \overline{B}$ equivalent to??

$$ \overline{A + B} $$

What is De Morgan’s second law??

$$ \overline{A \cdot B} = \overline{A} + \overline{B} $$

What is $\overline{A \cdot B}$ equivalent to??

$$ \overline{A} + \overline{B} $$

In boolean algebra, simplify $X \cdot 0$$??

$0$

In boolean algebra, simplify $X \cdot 1$??

$X$

In boolean algebra, simplify $X \cdot X$??

$X$

In boolean algebra, simplify $X \cdot \overline{X}$??

$0$

In boolean algebra, simplify $X + 1$??

$X$

In boolean algebra, simplify $X + 1$??

$1$

In boolean algebra, simplify $X + X$??

$X$

In boolean algebra, simplify $X + \overline{X}$??

$1$

In boolean algebra, simplify $\overline{\overline{X}}$??

$X$

What is the commutative rule??

The order of operations does not matter.

Because of the commutative rule, what is $X \cdot Y$ equivalent to??

$$ Y \cdot X $$

What is the associative rule??

Doing A then B is the same as doing B then A.

Because of the associative rule, what is $X \cdot (Y \cdot Z)$ equivalent to??

$$ (X \cdot Y) \cdot Z $$

What is the distributive rule??

Applying an operand to a bracket is the same as applying the operand to each term of the bracket.

Because of the distributive rule, what is $X \cdot (Y + Z)$ equivalent to??

$$ X \cdot Y + X \cdot Z $$

In boolean algebra, simplify $(A \cdot \overline{A}) + B$??

$$ B $$

In boolean algebra, simplify $(A \cdot B) + (\overline{A} \cdot B)$??

$$ B $$

In boolean algebra, simplify $A \cdot B + A \cdot (B + C)$??

$$ A \cdot (B + C) $$


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date: 2020-09-08 10:08
tags:
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- '@?school'
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title: Computing - Boolean Algebra